Projection system and automatic setting method thereof

ABSTRACT

A projection system including a processing device and a first projector is provided. The first projector includes a first projection unit and a first image capturing unit. The first projection unit is configured to sequentially project a first reference image and a second reference image. The first image capturing unit is configured to sequentially obtain a first captured image and a second captured image. The processing device is adapted to compare the first captured image and the second captured image to obtain a position of an image region having a pixel value change among the first captured image and the second captured image. The processing device defines the position of the image block having the pixel value change as a valid identification region. In addition, an automatic setting method is also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of China application serialno. 201710910336.5, filed on Sep. 29, 2017. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND 1. Field of the Invention

The invention relates to a projection technique, and more particularly,to a projection system and an automatic setting method thereof.

2. Description of Related Art

In general, a plurality of projectors may be integrated as oneprojection system for projecting stitching image frames in large area.In other words, the projectors can project a plurality project partialimage frames so the partial images can be integrated on a projectionplane in order to display an integrated image frame in large area.However, in the conventional art, a common projection system usuallyrequires a large number of devices to be disposed, and requires complexmanual settings to be made on the projectors (i.e., setting parametersmust be manually adjusted for each of the projectors). Consequently, ittakes a lot of time to set up the projection system, which results in anincreasing installation cost for the projection system. Therefore,finding a way to provide the projection system with advantage of easyset up while allowing the projection system to automatically adjustrelated setting parameters in an automatic setting manner so theprojectors can accurately project the partial image frames onto theprojection plane to be integrated into the integrated image frame inlarge area is one of the important issues to be addressed.

The information disclosed in this Background section is only forenhancement of understanding of the background of the describedtechnology and therefore it may contain information that does not formthe prior art that is already known to a person of ordinary skill in theart. Further, the information disclosed in the Background section doesnot mean that one or more problems to be resolved by one or moreembodiments of the invention were acknowledged by a person of ordinaryskill in the art.

SUMMARY

The invention is directed to a projection system and an automaticsetting method thereof, which are capable of automatically determining avalid identification region of captured images captured by projectors ofthe projection system and automatically adjusting projection imageranges of the projectors to integrate projection images of theprojectors into one integrated projection image with favorableprojection quality.

To achieve one, a part, or all of the objectives or other objectives, anembodiment of the invention provides an automatic setting method adaptedto a projection system. The projection system includes a processingdevice and a first projector. The first projector includes a firstprojection unit and a first image capturing unit. The method includes:projecting a first reference image onto a projection plane by the firstprojection unit, and capturing the first reference image on theprojection plane by the first image capturing unit to obtain a firstcaptured image; projecting a second reference image onto the projectionplane by the first projection unit, and capturing the second referenceimage on the projection plane by the first image capturing unit toobtain a second captured image; and comparing the first captured imageand the second captured image to obtain a position of an image regionhaving a pixel value change among the first captured image and thesecond captured image, and defining the position of the image blockhaving the pixel value change as a valid identification region.

To achieve one, a part, or all of the objectives or other objectives, anembodiment of the invention provides a projection system including aprocessing device and a first projector. The first projector is coupledto the processing device. The first projector includes a firstprojection unit and a first image capturing unit. The first projectionunit is configured to project a first reference image onto a projectionplane. The first image capturing unit is configured to capture the firstreference image on the projection plane to obtain a first capturedimage. The processing device projects a second reference image onto theprojection plane by the first projection unit. The processing devicecaptures the second reference image on the projection plane by the firstimage capturing unit to obtain a second captured image. The processingdevice is adapted to compare the first captured image and the secondcaptured image to obtain a position of an image region having a pixelvalue change among the first captured image and the second capturedimage. The processing device defines the position of the image blockhaving the pixel value change as a valid identification region.

Based on the above, the projection system and the automatic settingmethod thereof of the invention can effectively determine the valididentification region in the captured images captured by the projectorsso as to effectively reduce time for image analysis and computing aswell as data computing amount. Moreover, the projection system and theautomatic setting method thereof of the invention can automaticallyintegrate the projection images of the projectors into one integratedprojection image with favorable projection quality.

Other objectives, features and advantages of the invention will befurther understood from the further technological features disclosed bythe embodiments of the invention wherein there are shown and describedpreferred embodiments of this invention, simply by way of illustrationof modes best suited to carry out the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a schematic diagram illustrating a projection system in anembodiment of the invention.

FIG. 2 is a flowchart illustrating an automatic setting method in anembodiment of the invention.

FIG. 3A is a side view of a projector in an embodiment of the invention.

FIG. 3B is a schematic diagram illustrating an image frame in anembodiment of the invention.

FIG. 3C is a schematic diagram illustrating a captured image in anembodiment of the invention.

FIG. 4A to FIG. 4D are schematic diagrams illustrating captured imagesin another embodiment of the invention.

FIG. 5 is a flowchart illustrating an automatic setting method inanother embodiment of the invention.

FIG. 6A is a schematic diagram illustrating a first projection mode ofthe projection system in an embodiment of the invention.

FIG. 6B is a schematic diagram illustrating a second projection mode ofthe projection system in an embodiment of the invention.

FIG. 6C is a schematic diagram illustrating a third projection mode ofthe projection system in an embodiment of the invention.

FIG. 6D is a schematic diagram illustrating a fourth projection mode ofthe projection system in an embodiment of the invention.

FIG. 7 is a flowchart illustrating an automatic setting method inanother embodiment of the invention.

FIG. 8A is a schematic diagram illustrating a first reference image inan embodiment of the invention.

FIG. 8B is a schematic diagram illustrating a second reference image inan embodiment of the invention.

FIG. 9 is a flowchart illustrating an automatic setting method inanother embodiment of the invention.

FIG. 10A is a schematic diagram illustrating a third reference image inan embodiment of the invention.

FIG. 10B is a schematic diagram illustrating a fourth reference image inan embodiment of the invention.

FIG. 11 is a schematic diagram illustrating two projectors in anembodiment of the invention.

FIG. 12 is a schematic diagram illustrating a coordinate integration inthe embodiment in FIG. 11.

FIG. 13A is a schematic diagram illustrating two image projection areasoverlapping with each other in the embodiment of FIG. 11.

FIG. 13B is a schematic diagram illustrating an integrated image framearea in the embodiment of FIG. 11.

DESCRIPTION OF THE EMBODIMENTS

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings which form a part hereof,and in which are shown by way of illustration specific embodiments inwhich the invention may be practiced. In this regard, directionalterminology, such as “top,” “bottom,” “front,” “back,” etc., is usedwith reference to the orientation of the Figure(s) being described. Thecomponents of the invention can be positioned in a number of differentorientations. As such, the directional terminology is used for purposesof illustration and is in no way limiting. On the other hand, thedrawings are only schematic and the sizes of components may beexaggerated for clarity. It is to be understood that other embodimentsmay be utilized and structural changes may be made without departingfrom the scope of the invention. Also, it is to be understood that thephraseology and terminology used herein are for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. Unless limited otherwise, the terms“connected,” “coupled,” and “mounted” and variations thereof herein areused broadly and encompass direct and indirect connections, couplings,and mountings. Similarly, the terms “facing,” “faces” and variationsthereof herein are used broadly and encompass direct and indirectfacing, and “adjacent to” and variations thereof herein are used broadlyand encompass directly and indirectly “adjacent to”. Therefore, thedescription of “A” component facing “B” component herein may contain thesituations that “A” component directly faces “B” component or one ormore additional components are between “A” component and “B” component.Also, the description of “A” component “adjacent to” “B” componentherein may contain the situations that “A” component is directly“adjacent to” “B” component or one or more additional components arebetween “A” component and “B” component. Accordingly, the drawings anddescriptions will be regarded as illustrative in nature and not asrestrictive.

FIG. 1 is a schematic diagram illustrating a projection system in anembodiment of the invention. With reference to FIG. 1, a projectionsystem 100 includes a processing device 110 and a plurality ofprojectors 120_1, 120_2 to 120_N, wherein N is a positive integergreater than 0. The processing device 110 includes a controller 111 andan image processor 112. The projectors 120_1, 120_2 to 120_N includeprojection units 121_1, 121_2 to 121_N and image capturing units 122_1,122_2 to 122_N, respectively. In the embodiment, the projection units121_1, 121_2 to 121_N may further include a light source module (e.g., alighting apparatus having a discharge lamp, a light-emitting diode or alaser device), a light machine (which includes a light modulator, suchas a reflective or transmissive space light modulator; the reflectivespace light modulator includes a liquid crystal on silicon (LCOS), adigital micro-mirror device (DMD), etc.; the transmissive space lightmodulator includes a transparent liquid crystal panel, etc.). Further,based on different methods for inputting control signals, the lightmodulator includes, for example, an optically addressed spatial lightmodulator (OASLM) or an electrically addressed spatial light modulator(EASLM), a projection lens group (including a plurality of lenses) andan image output unit (e.g., an I/O port or an interface for outputtingsignal, which can transmit an image content signal (video signal) or acontrol signal through Bluetooth, Wi-Fi, Zigbee or other wirelessmethods as well as an optical fiber or other wired transmissioninterfaces). The image capturing units 122_1, 122_2 to 122_N may becameras. In the embodiment, the projection system 100 projects aplurality of image frames by the projectors 120_1, 120_2 to 120_N, andpresents one integrated image frame by integrating these image frames.The projection system 100 captures a plurality of captured images fromrespective image capturing areas on a projection plane (e.g., FIG. 3A)by the image capturing units 122_1, 122_2 to 122N. Afterwards, theprocessing device 110 can analyze the captured images captured by theimage capturing units 122_1, 122_2 to 122 N and compare the capturedimages with the image frames projected by the corresponding projectors120_1, 120_2 to 120_N in order to adjust related projection settings forthe projectors 120_1, 120_2 to 120_N. In addition, a capturing range ofthe image capturing units 122_1, 122_2 to 122_N is greater than aprojecting range of the projectors 120_1, 120_2 to 120_N.

In the embodiment, the controller 111 may be disposed in, for example, adesktop computer, a personal computer (PC), a portable terminal product,a personal digital assistor (PDA), a tablet PC, etc. Further, thecontroller 111 may include a central processing unit (CPU) with imagedata processing and computing functions, or other programmable devicesfor general purpose or special purpose, such as a microprocessor, adigital signal processor (DSP), an image processing unit (IPU), agraphics processing unit (GPU), a programmable controller, anapplication specific integrated circuits (ASIC), a programmable logicdevice (PLD), other similar processing devices or a combination of theabove devices.

In the embodiment, each of the controller 111 and the image processor112 may further include a storage device. The storage device may be usedto store image processing programs, image data, data computing programsor coordinate conversion equations. In the embodiment, the controller111 may be used to execute an analysis operation for the capturedimages, an integration operation for the image frames and various imageprocessing operations. In the embodiment, the image processor 112 is,for example, a blending box (e.g., Optoma, GB-200 multifunctional imagewarping and blending processor). Further, the image processor 112 may bedisposed outside the controller 111 or integrated with the controller111 as the same device. However, the invention is not limited thereto.

In the embodiment, the image processor 112 is coupled to the controller111. The controller 111 is configured to output image frame data,control signals and image frame integration setting values to the imageprocessor 112 so the image processor 112 can distribute the image framedata provided by the controller 111 according to the image frameintegration setting values. The image processor 112 can transmit thedistributed image frame data and the related projection setting valuesto the projectors 120_1, 120_2 to 120_N respectively so each of theprojectors 120_1, 120_2 to 120_N can project a partial image framerelative to the distributed image frame data in order to display oneintegrated image frame. Here, the image frame data refers to imagecontent files or image files predetermined to be projected, and thecontrol signals are used to control operations of the projectors and theimage capturing units.

In another embodiment, the controller 111 is coupled to the imageprocessor 112, and the controller 111 is configured to output the imageframe data to the image processor 112. The image processor 112 thentransmits the image frame data to the projectors 120_1, 120_2 to 120_Nfor projecting the image frames relative to the image frame data.Further, the controller 111 is coupled to the projectors 120_1, 120_2 to120_N to provide the control signals to the image processor 112 and theprojectors 120_1, 120_2 to 120_N by other transmission means (e.g.,RJ-45) so as to control operations of the image processor 112 and theprojectors 120_1, 120_2 to 120_N.

In other embodiments, the controller 111 is coupled to the imageprocessor 112, and the controller 111 is configured to output the imageframe data and the control signals to the image processor 112. Afterthat, the image processor 112 transmits the image frame data to theprojectors 120_1, 120_2 to 120_N for projecting the image framesrelative to the image frame data.

Specifically, before the projection system 100 executes normalprojection tasks, the projection system 100 can utilize the controller111 to automatically set the projectors 120_1, 120_2 to 120_N andautomatically set the image frame integration setting values in advance.When the projection system 100 is executing the normal projection tasks,the image processor 112 can process the image frames provided by thecontroller 111 according to the automatically set image frameintegration setting values so as to drive the projectors 120_1, 120_2 to120_N for projecting the image frames. In the embodiment, the projectors120_1, 120_2 to 120_N can project multiple image frames onto the sameposition or different positions on the projection plane.

FIG. 2 is a flowchart illustrating an automatic setting method in anembodiment of the invention. With reference to FIG. 1 and FIG. 2, theautomatic setting method of FIG. 2 is adapted to the projection system100 of FIG. 1. In step S210, the projectors 121_1, 121_2 to 121_Nproject a plurality of image frames onto a projection plane, whereineach of the image frames includes a grid point array. In step

S220, the image capturing units 122_1, 122_2 to 122_N separately capturethe image frames on the projection plane according to a plurality ofsetting parameters to obtain a plurality of captured imagescorresponding to the setting parameters. In step S230, the processingdevice 110 can analyze the captured images to separately determinewhether the captured images meet a preset image condition. In step S240,when one of the captured images meets the preset image condition, theprocessing device 110 selects the one of the captured images meeting theimage condition as a desired captured image. In step S250, theprocessing device 110 sets one of the setting parameters correspondingto the desired captured image as a desired setting parameter, and setsthe image capturing units according to the desired setting parameter. Inmanufacturing, each of the image capturing units 122_1, 122_2 to 122_Nmay have different image-capturing functions. Therefore, based on themethod described above, the processing device 110 can automatically andseparately set the image capturing units 122_1, 122_2 to 122_N so theimage capturing units 122_1, 122_2 to 122_N can capture the capturedimages with favorable picture quality, which can assist the processingdevice 110 to effectively and accurately analyze the captured images.

In other words, in the embodiment, the projectors 120_1, 120_2 to 120_Nof the projection system 100 can execute the setting parameters of theimage capturing units 122_1, 122_2 to 122_N in advance so the imagecapturing units 122_1, 121_2 to 122_N can obtain the captured imageswith favorable picture quality. In this way, each the projectors 120_1,120_2 to 120_N can automatically execute an adjustment for the imageframe so the processing device 110 can effectively analyze or comparethe captured images provided by the projectors 120_1, 120_2 to 120_N andthe corresponding image frames thereby effectively preventingmisjudgments. Description is provided below in more details usingschematic diagrams of FIG. 3 to FIG. 4D.

FIG. 3A is a side view of a projector in an embodiment of the invention.With reference to FIG. 3A, in the embodiment, a projector 320 is mountedonto a fixed target B. Also, the projector 320 is disposed above aprojection plane S1 so the projector 320 can project an image lightsource PI onto the projection plane S1 from top to bottom. Here, theprojection plane S1 is a plane formed by a second direction P2 and athird direction P3. In the embodiment, the fixed target B can extend ona plane formed by a first direction P1 and the third direction P3. Also,the fixed target B may be, for example, a ceiling or a supportingmember, and the projection plane S1 may be a curtain or a wall. In otherembodiments, the fixed target B may also extend on the plane formed bythe second direction P2 and the third direction P3, which is notparticularly limited in the invention. The first direction P1, thesecond direction P2 and the third direction P3 are perpendicular to oneanother. It should be noted that, a disposition method for theprojectors described in each of the embodiments of the invention is notlimited by what illustrated in FIG. 3A. In an embodiment, the projector320 may also be disposed below the projection plane S1 so the projector320 can project the image light source PI onto the projection plane S1from bottom to top.

FIG. 3B is a schematic diagram illustrating an image frame in anembodiment of the invention. FIG. 3C is a schematic diagram illustratinga captured image in an embodiment of the invention. With reference toFIG. 2 to FIG. 3C, in the embodiment, a processing device 310 is coupledto a projector 320. First of all, a projection unit of the projector 320projects an image frame 301 as shown in FIG. 3B onto the projectionplane S1, wherein the image frame 301 include a grid point array 302. Inthe embodiment, the grid point array 302 is formed by a plurality ofgrid points arranged in sequence, and the grid points have an identicalsize and an equal distance spaced apart from the others. Next, an imagecapturing unit of the projector 320 captures the image frame on theprojection plane S1 according to a plurality of setting parameters toobtain a plurality of captured images corresponding to the settingparameters. Here, one of the captured images may be, for example, acaptured image 303 shown in FIG. 3C. It should be noted that, the imageframe 301 projected by the projection unit of the projector 320 viewingfrom the front is shown by FIG. 3B. Because the captured image 303 iscaptured by the image capturing unit of the projector 320 from aposition of the projector 320, an image frame 301′ and a grid pointarray 302′ in the captured image 303 are displayed in a frame tilted byan angle. In the embodiment, a size range of the captured image 303 isgreater than a size range of the image frame 301.

For instance, FIG. 4A to FIG. 4D are schematic diagrams for capturedimage in another embodiment of the invention. With reference to FIG. 2to FIG. 4D, the captured images obtained according to the settingparameters by the image capturing unit of the projector 320 may be, forexample, captured images 303A, 303B, 303C and 303D shown in FIG. 4A toFIG. 4D. It should be noted that, the image capturing unit of theprojector 320 can sequentially obtain the captured images 303A, 303B,303C and 303D according to the setting parameters such as differentexposure values or shutter capture speed parameters. In the embodiment,the processing device 310 analyzes the captured images to separatelydetermine whether the captured images meet the preset image condition.

In the embodiment, the preset image condition may be, for example, acalculation or analysis on a plurality of grayscale average values, aplurality of grid point quantities or light band areas of the capturedimages 303A, 303B, 303C and 303D. The processing device 310 can decidescreen clarity for the captured images 303A, 303B, 303C and 303D bydetermining whether the grayscale average values are greater than athreshold value, determining whether the grid point quantities are equalto a preset quantity, or determining whether the light band areas areequal to a preset area. Here, the light band area is determined bychecking whether an area in which all of the grayscale values beinghigher than the threshold value in the captured image is equal to thepreset area. In other embodiments, the preset image condition may alsobe a default image condition. Accordingly, the processing device 310 canselect one of the captured images 303A, 303B, 303C and 303D as thedesired captured image according to the preset image condition. Also,the processing device 310 sets one of the setting parameters (e.g.,settings like the exposure values or the shutter capture speedparameters) corresponding to the desired captured image as the desiredsetting parameter, and sets the image capturing units according to thedesired setting parameter.

More specifically, the captured image 303C and the captured image 303Dare difficult to recognize because some of the grid points in them areconnected together due to exposure. On the other hand, it can be seenthat the captured image 303A and the captured image 303B have the samegrid point quantities. However, the grayscale average value of each ofthe grid points of the captured image 303B is higher than the thresholdvalue, whereas the grayscale average value of each of the grid points ofthe captured image 303A is lower than the threshold value. Therefore,the processing device 310 will determine that a picture quality of thecaptured image 303B is higher than a picture quality of the capturedimage 303A. In this example, the processing devices 310 selects thecaptured image 303B as the desired captured image, and sets the settingparameter corresponding to the captured image 303B as the desiredsetting parameter. Accordingly, the processing device 310 of theembodiment is capable of automatically adjusting the image capturingunit of the projector 320. However, in an embodiment, if all of thecaptured images 303A, 303B, 303C and 303D fail to meet the reset imagecondition, the processing device 310 can further project a prompt imageonto the projection plane S1 by the projection unit of the projector320, so as to remind the user that the setting parameter of theprojector 320 or an environmental factor are to be adjusted manually.The environmental factor may include an ambient light or other factorsthat may influence the projection. For example, a brightness of theambient light may be adjusted to solve the issue, but the invention isnot limited thereto.

FIG. 5 is a flowchart illustrating an automatic setting method inanother embodiment of the invention. With reference to FIG. 1 and FIG.5, the automatic setting method of FIG. 5 is adapted to the projectionsystem 100 of FIG. 1. In step S510, the processing device 110 determineswhether a plurality of projectors are in a top-down projection mode orin a bottom-up projection mode (i.e., whether the projector is placed inan upside-down manner or the projector is placed in a normal manner)according to a firmware setting of each of the projectors, so as to knowof whether the projectors are disposed above a projection plane or belowthe projection plane. In step S520, the processing device 110sequentially projects a projection mode determination image by a part ofthe projectors 120_1, 120_2 to 120_N disposed above the projectionplane, wherein the projection mode determination image includes aplurality of grid points. In step S530, when one of the projectors120_1, 120_2 to 120_N disposed above the image plane projects theprojection mode determination image, remainders of the image capturingunits 122_1, 122_2 to 122_N of the projectors 120_1, 120_2 to 120_Nobtain captured images from respective image capturing areas on theprojection plane. In step S540, the processing device 110 analyzes thecaptured images captured from the respective image capturing areas bythe remainders of the projectors 120_1, 120_2 to 120_N disposed abovethe projection plane or below the projection plane, so as to determineprojection modes of the projectors 120_1, 120_2 to 120_N. In this way,the processing device 110 can automatically determine whether the imagecapturing units 122_1, 122_2 to 122_N project the same image framesoverlapping with one another or separately project different imageframes in order to automatically set contents for the image framesprojected by the projectors 120_1, 120_2 to 120_N.

Further, in the embodiment, the processing device 110 can also determinea disposing sequence of each of the projectors 120_1, 120_2 to 120_N. Inthe embodiment, the processing device 110 can analyze a position of atleast one of the grid points of the projection mode determination imagein the captured images captured from the respective image capturingareas by the remainders of the projectors 120_1, 120_2 to 120_N disposedabove the projection plane or below the projection plane, so as todetermine the disposing sequence of each of the projectors 120_1, 120_2to 120_N. In other words, when the user intends to set up the projectors120_1, 120_2 to 120_N of the projection system 100, the user does notneed to manually set the contents for the image frames to berespectively projected by the projectors 120_1, 120_2 to 120_N accordingto a disposed position of each of the projectors 120_1, 120_2 to 120_N.The projection system 100 of the invention can automatically determinethe disposed position and the projection mode for each of the projectors120_1, 120_2 to 120_N.

Description is provided below in more details using schematic diagramsof FIG. 6A to FIG. 6D in combination with the automatic setting methodof FIG. 5.

FIG. 6A is a schematic diagram illustrating a first projection mode ofthe projection system in an embodiment of the invention. With referenceto FIG. 5 and FIG. 6A, in the embodiment, a processing device 610 iscoupled to projectors 620_1 to 620_6. The projectors 620_1 to 620_6sequentially project respective image frames on respective imagecapturing areas 601_1 to 601_6 on the projection plane S1. In theembodiment, the projectors 620_1 to 620_6 are disposed above theprojection plane S1, but the invention is not limited thereto. In anembodiment, the projectors 620_1 to 620_6 may also be disposed below theprojection plane S1.

In the embodiment, first of all, the processing device 610 executes stepS510 so the projectors 620_1 to 620_6 can determine whether the disposedpositions of the projectors 620_1 to 620_6 are above the projectionplane S1 or below the projection plane S1 according to the respectivefirmware settings. Herein, the firmware settings may be preset by theuser using an on screen display (OSD) adjusting function or remotecontroller of the projector or may be automatically determined by eachof the projectors 620_1 to 620_6. Next, the processing device 610executes step S520 so the projectors 620_1 to 620_6 can sequentiallyproject the projection mode determination image on the correspondingimage capturing areas 601_1 to 601_6. Then, the processing device 610executes step S530, in which when one of the projectors 620_1 to 620_6projects the projection mode determination image, the remainders of theprojectors 620_1 to 620_6 obtain the respective captured images from therespective image capturing areas 601_1 to 601_6 on the projection planeS1. Lastly, the processing device 610 executes step S540, in which theprocessing device 610 analyzes the respective captured images capturedfrom the respective image capturing areas by the remainders of theprojectors 620_1 to 620_6 disposed above the projection plane S1, so asto determine the projection modes of the projectors 620_1 to 620_6.

For instance, when the projector 620_3 projects the projection modedetermination image on the corresponding image capturing area 601_3, theremainders of the projectors (i.e., 620_1, 620_2, 620_4, 620_5 and620_6) can simultaneously obtain the captured images from the respectiveimage capturing areas (i.e., 601_1, 601_2, 601_4, 601_5 and 601_6). Itshould be noted, in the embodiment, the projection mode determinationimage may be an image frame on the image capturing area 601_3 as shownin FIG. 6A, and the projection mode determination image includes aplurality of grid points GP respectively in a left-side region and aright-side region. Accordingly, the processing device 610 can analyzethe captured images captured from the respective image capturing areas(i.e., 601_1, 601_2, 601_4, 601_5 and 601_6) by the remainders of theprojectors (i.e., 620_1, 620_2, 620_4, 620_5 and 620_6). In theembodiment, because none of the captured images captured by theremainders of the projectors (i.e., 620_1, 6202, 620_4, 620_5 and 620_6)shows all of the grid points GP of the projection mode determinationimage, the processing device 610 can determine that the projector 620_3does not have overlapping projection with the projectors 620_1, 620_2,620_4, 620_5 and 620_6. By analogy, the processing device 610 candetermine the projection modes of the projectors 620_1 to 620_6.

FIG. 6B is a schematic diagram illustrating a second projection mode ofthe projection system in an embodiment of the invention. With referenceto FIG. 5 and FIG. 6B, in the embodiment, a processing device 710 iscoupled to projectors 720_1 to 720_6. The projectors 720_1 to 720_6sequentially project image frames on respective image capturing areas701_1 to 701_6 on the projection plane S1. In the embodiment, theprojectors 720_1 to 720_6 are disposed above the projection plane S1,but the invention is not limited thereto. In an embodiment, theprojectors 720_1 to 720_6 may also be disposed below the projectionplane S1.

In the embodiment, first of all, the processing device 710 executes stepS510 so the projectors 720_1 to 720_6 can determine whether the disposedpositions of the projectors 720_1 to 720_6 are above the projectionplane S1 or below the projection plane S1 according to the respectivefin iware settings. Next, the processing device 710 executes step S520so the projectors 720_1 to 720_6 can sequentially project the projectionmode determination image on the corresponding image capturing areas701_1 to 701_6. Then, the processing device 710 executes step S530, inwhich when one of the projectors 720_1 to 720_6 projects the projectionmode determination image, the remainders of the projectors 720_1 to720_6 obtain the respective captured images from the respective imagecapturing areas 701_1 to 701_6 on the projection plane S1. Lastly, theprocessing device 710 executes step S540, in which the processing device710 analyzes the respective captured images captured from the respectiveimage capturing areas by the remainders of the projectors 720_1 to 720_6disposed above the projection plane S1, so as to determine theprojection modes of the projectors 720_1 to 7206.

For instance, when the projector 720_3 projects the projection modedetermination image on the corresponding image capturing area 701_3, theremainders of the projectors (i.e., 720_1, 720_2, 720_4, 720_5 and720_6) can simultaneously or sequentially obtain the captured imagesfrom the respective image capturing areas (i.e., 701_1, 701_2, 701_4,701_5 and 701_6). It should be noted, in the embodiment, the projectionmode determination image may be an image frame on the image capturingarea 701_3 shown in FIG. 6B, and the projection mode determination imageincludes a plurality of grid points respectively in a left-side regionand a right-side region. Accordingly, the processing device 710 cananalyze the captured images captured from the respective image capturingareas (i.e., 701_1, 701_2, 701_4, 701_5 and 701_6) by the remainders ofthe projectors (i.e., 720_1, 720_2, 720_4, 720_5 and 720_6). In theembodiment, because the captured image captured by the projector 720_4shows all of the grid points GP of the projection mode determinationimage, the processing device 710 can determine that the projector 720_3has overlapping projection with the projector 720_4. However, becausenone of the captured images captured by the projector 720_1, 720_2,720_5 and 720_6 shows all of the grid points GP of the projection modedetermination image, the processing device 710 can determine that theprojectors 720_1, 720_2, 720_5 and 720_6 do not have overlappingprojection with the projectors 720_3 and 720_4. By analogy, theprocessing device 710 can determine the projection modes of theprojectors 720_1 to 720_6. Incidentally, the overlapping projection oftwo projectors is applicable to special projection environments such asa darker projection environment or a projection plane with relativelypoor reflective degree. With the same image frame repeatedly projectedby the two projectors onto one image projection area, brightness orclearness of the image frame may be increased.

Further, in this example, the processing device 710 can further analyzethe captured images captured from the respective image capturing areas(i.e., 701_1, 701_2, 701_4, 701_5 and 701_6) by the remainders of theprojectors (i.e., 720_1, 720_2, 720_4, 720_5 and 720_6). In thisexample, because the projectors 720_1 and 720_2 project images on theimage capturing areas 701_1 and 701_2 at an overlapping position, theprojectors 720_1 and 720_2 may be regarded as one group without havingdifferences in sequence. Similarly, the projectors 720_3 and 720_4 maybe regarded as one group and the projectors 720_5 and 720_6 may beregarded as one group. In other words, because the captured imagescaptured from the respective image capturing areas 701_1, 701_2, 701_5and 701_6 by the image capturing units of the projectors 720_1, 720_2,720_5 and 720_6 include a part of the grid points GP in the projectionmode determination image projected by the projector 720_3, theprocessing device 710 can determine the positions of the part of thegrid points GP shown in the captured images captured by the projectors720_1, 720_2, 720_5 and 720_6, and then determine whether the imageframes projected by the projectors 720_1, 720_2, 720_5 and 720_6 areoverlapping with one another.

FIG. 6C is a schematic diagram illustrating a third projection mode ofthe projection system in an embodiment of the invention. FIG. 6D is aschematic diagram illustrating a fourth projection mode of theprojection system in an embodiment of the invention. With reference toFIG. 5, FIG. 6C and FIG. 6D, in the embodiment, a processing device 810is coupled to projectors 820_1 to 820_6. The projectors 820_1 to 820_6sequentially project image frames on respective image capturing areas801_1 to 801_6 on the projection plane S1. In the embodiment, theprojectors 820_1 to 820_3 are disposed above the projection plane S1,and the projectors 820_4 to 820_6 are disposed below the projectionplane S1.

In the embodiment, first of all, the processing device 810 executes stepS510 so the projectors 820_1 to 820_6 can determine whether the disposedpositions of the projectors 820_1 to 8206 are above the projection planeS1 or below the projection plane S1 according to the respective firmwaresettings. Next, the processing device 810 executes step S520 so theprojectors 820_1 to 820_6 can sequentially project the projection modedetermination image on the corresponding image capturing areas 801_1 to801_6. Then, the processing device 810 executes step S530, in which whenone of the projectors 820_1 to 820_6 projects the projection modedetermination image, the remainders of the projectors 820_1 to 820_6obtain the respective captured images from the respective imagecapturing areas 801_1 to 801_6 on the projection plane S1. Lastly, theprocessing device 810 executes step S540, in which the processing device810 analyzes the captured images captured from the respective imagecapturing areas by the remainders of the projectors 820_1 to 820_6disposed above the projection plane S1, so as to determine theprojection modes of the projectors 820_1 to 820_6.

Specifically, when the projector 820_2 projects the projection modedetermination image on the corresponding image capturing area 801_2, theremainders of the projectors (i.e., 820_1, 820_3, 8204, 820_5 and 820_6)can simultaneously obtain the captured images from the respective imagecapturing areas (i.e., 801_1, 801_3, 801_4, 801_5 and 801_6). It shouldbe noted, in the embodiment, the projection mode determination image maybe an image frame on the image capturing area 801_2 as shown in FIG. 6C,and the projection mode determination image includes a plurality of gridpoints GP respectively in a left-side region, a right-side region and alower-side region. Here, the grid points GP are arranged in form of anL-shape. Accordingly, the processing device 810 can analyze the capturedimages captured from the respective image capturing areas (i.e., 801_1,801_3, 801_4, 801_5 and 801_6) by the remainders of the projectors(i.e., 820_1, 820_3, 820_4, 820_5 and 820_6). In the embodiment, none ofthe captured images captured by the projectors 820_1, 820_3, 820_4,820_5 and 820_6 shows all of the grid points GP of the projection modedetermination image.

Further, in this example, the processing device 810 can further analyzethe captured images captured from the respective image capturing areas(i.e., 801_1, 801_3, 801_4, 801_5 and 801_6) by the remainders of theprojectors (i.e., 820_1, 820_3, 820_4, 820_5 and 820_6). In thisexample, because the captured images captured from the respective imagecapturing areas 801_1 and 801_3 by the image capturing units of theprojectors 820_1 and 820_3 include a part of the grid points GP in theprojection mode determination image projected by the projector 820_2,the processing device 810 can determine that the part of the grid pointsGP is shown in the captured images captured by the projectors 820_1 and820_3 at a right-side position and a left-side position, respectively,and then determine that the projectors 820_1 and 820_3 are located on aleft-side and a right-side of the projector 820_2, respectively. In thisexample, because the captured images captured from the respective imagecapturing areas 801_4 and 801_6 by the image capturing units of theprojectors 820_4 and 820_6 include a part of the grid points GP in theprojection mode determination image projected by the projector 820_2,the processing device 810 can determine that the part of the grid pointsGP is shown in the captured images captured by the projectors 820_4 and820_6 at an upper-side position, and then determine that the projectors820_4 and 820_6 are located on a lower-side of the projector 820_2. Inaddition, in the image capturing area 801_5 corresponding to theprojector 820_5, since there are more grid points GP in the capturedimage captured by the projector 820_5 (than the grid pints GP in theother projectors) while the grid points GP in the captured image arelocated on an upper-side, it can be determined that the projector 820_5is located right under the projector 820_2.

With reference to FIG. 6D, in this example, when the projector 820_5projects the projection mode determination image in the correspondingimage capturing area 801_5, the remainders of the projectors (i.e.,820_1, 820_2, 820_3, 820_4 and 820_6) simultaneously or sequentiallyobtain the captured images from the respective image capturing areas(i.e., 801_1, 820_2, 801_3, 801_4 and 801_6). In the embodiment, theprojection mode determination image may be an image frame on the imagecapturing area 801_5 as shown in FIG. 6D, and the projection modedetermination image includes a plurality of grid points GP respectivelyin a left-side region, a right-side region and an upper-side region.Here, the grid points GP are arranged in form of an L-shape. Because thecaptured images captured from the respective image capturing area 801_2by the image capturing unit of the projector 820_2 includes a part ofthe grid points GP in the projection mode determination image projectedby the projector 820_5, the processing device 810 can determine that thepart of the grid points GP is shown in the captured image captured bythe projectors 820_2 at a lower-side position, and then determine thatthe projector 820_2 is located right above the projector 820_5 based onthe number and the position of the part of the grid points GP. Also, theprocessing device 810 can determine that the part of the grid points GPis also shown in the captured images captured by the projectors 820_4and 820_6 at a right-side position and a left-side position,respectively, and then determine that the projectors 820_4 and 820_6 arelocated on a left-side and a right-side of the projector 820_5,respectively. In this example, in the captured images captured from therespective image capturing areas 801_1 and 801_3 by the image capturingunits of the projectors 820_1 and 820_3, the part of the grid points GPin the projection mode determination image projected by the projector820_5 is not captured by the projector 820_1. However, in the capturedimage captured from the respective image capturing area 801_3 by theimage capturing unit of the projector 820_3, the part of the grid pointsGP in the projection mode determination image projected is captured.Therefore, the processing device 810 can determine that the part of thegrid points is shown in the captured image captured by the projector820_3 at a lower-side position, and then determine that the projector820_3 is located on an upper-side of the projector 820_5. By analogy,after the projection mode determination image is sequentially projectedby the projectors 820_1 to 820_6, the processing device 810 candetermine disposing relations among the projectors 820_1 to 820_6 so asto determine the disposing sequence of each of the projectors 820_1 to820_6.

FIG. 7 is a flowchart illustrating an automatic setting method inanother embodiment of the invention. With reference to FIG. 1 and FIG.7, the automatic setting method of FIG. 7 is adapted to the projectionsystem 100 of FIG. 1. In the embodiment, the projector 120_1 includesthe projection unit 121_1 and the image capturing unit 122_1. In stepS910, the processing device 110 projects a first reference image onto aprojection plane by the projection unit 121_1, and captures the firstreference image on the projection plane by the image capturing unit122_1 to obtain a first captured image. In step S920, the processingdevice 110 projects a second reference image onto the projection planeby the projection unit 121_1, and captures the second reference image onthe projection plane by the image capturing unit 122_1 to obtain asecond captured image. In step S930, the processing device 110 isadapted to compare the first captured image and the second capturedimage to obtain a position of an image region having a pixel valuechange with a variation value greater than a preset value among thefirst captured image and the second captured image, and defines theposition of the image block having the pixel value change as a valididentification region. By analogy, the same operation may also beexecuted for the projectors 120_2 to 120_N, where the pixel value is atechnical term well-known by persons skilled in the art, which includesgrayscale values, etc., but not limited thereto.

In other words, because a range of the image capturing unit 122_1 forcapturing the captured image is greater than a range of the projectionunit 121_1 for projecting the image frame, the captured image capturedby the image capturing unit 122_1 may include a background image aroundthe image frame. In the embodiment, the processing device 110 canautomatically determine the valid identification region in the capturedimage captured by the image capturing unit 122_1. Accordingly, when theprocessing device 110 analyzes the captured image captured by the imagecapturing unit 122_1, the processing device 110 can simply process animage of the valid identification region instead of processing theentire captured image. In this way, the processing device 110 of theembodiment can effectively reduce time for image analysis and computingas well as data computing amount.

Description is provided below in more details using schematic diagramsof FIG. 8A to FIG. 8B in combination with the automatic setting methodof FIG. 7.

FIG. 8A is a schematic diagram illustrating a first reference image inan embodiment of the invention. With reference to FIG. 7, FIG. 8 andFIG. 8B, a processing device 1010 is coupled to a projector 1020. Firstof all, in FIG. 8A, a projection unit of the projector 1020 projects afirst reference image 1001A onto a projection plane. In the embodiment,the first reference image 1001A may be, for example, a pure-white imageor a pure-black image. Further, in the embodiment, an image capturingunit of the projector 1020 captures the image frame on the projectionplane to obtain a corresponding first captured image. Next, in FIG. 8B,the projection unit of the projector 1020 projects a second referenceimage 1001B onto the projection plane S1. In the embodiment, the secondreference image 1001B may be, for example, the pure-white image or thepure-black image different from the first reference image 1001A.Further, in the embodiment, the image capturing unit of the projector1020 captures the image frame projected on the projection plane toobtain a corresponding second captured image.

In the embodiment, as shown in FIG. 8A and FIG. 8B, with respect to thefirst captured image and the second captured image obtained by theprocessing device 1010, the first captured image includes the firstreference image 1001A and a background image BI and the second capturedimage includes the second reference image 1001B and the background imageBI. Accordingly, the processing device 1010 can subtract pixel values ofthe first captured image and the second captured image from each otherto obtain a pixels-subtracted image. Also, the processing device 1010can analyze the pixels-subtracted image to determine a region having thepixel values with the variation value greater than the preset value inthe pixels-subtracted image, and define the region having the pixelvalues with the variation value greater than the preset value as thevalid identification region. Relatively, the processing device 1010 cananalyze the pixels-subtracted image to determine a region having thepixel values with the variation value less than the preset value in thepixels-subtracted image, and define the region having the pixel valueswith the variation value less than the preset value as a non-valididentification region. In this way, the processing device 1010 of theembodiment can automatically determine the valid identification regionof the captured image captured by the projector 1020.

FIG. 9 is a flowchart illustrating an automatic setting method inanother embodiment of the invention. With reference to FIG. 1 and FIG.9, the automatic setting method of FIG. 9 is adapted to the projectionsystem 100 of FIG. 1. It should be noted that the automatic settingmethod of FIG. 9 may be executed subsequent to step S930 of FIG. 7, butthe invention is not limited thereto. In an embodiment, the automaticsetting method of FIG. 9 may also be executed independently. In theembodiment, the projector 120_1 includes the projection unit 121_1 andthe image capturing unit 122_1. In step S1110, the processing device 110projects a third reference image onto the projection plane at theposition corresponding to the valid identification region on theprojection plane by the projection unit 121_1. In step S1120, theprocessing device 110 captures the third reference image on theprojection plane by the image capturing unit 122_1 to obtain a thirdcaptured image. Here, the third reference image has four reference gridpoints arranged in a quadrangle, and located within the valididentification region. In step S1130, the processing device 110 analyzesthe third captured image to obtain four reference coordinates of thefour reference grid points in the third captured image. In step S1140,the processing device 110 generates a grid point-filled image accordingto the four reference coordinates of the four reference grid points, andprojects the grid point-filled image onto the projection plane by theprojection unit 121_1. Here, the grid point-filled image includes a gridpoint array formed by a plurality of grid points. In another embodiment,the four reference grid points may be a part of the grid point-filledimage, and the grid point-filled image is an image preset according to adefinition of the projector in the processing device. In step S1150, theprocessing device 110 captures a fourth captured image on the projectionplane by the image capturing unit 122_1, and analyzes the fourthcaptured image to obtain a plurality of grid point coordinates of thegrid points in the fourth captured image. In step S1160, the processingdevice 110 establishes a coordinate conversion relation between theprojection unit 121_1 and the image capturing unit 122_1 according tothe plurality of grid point coordinates. Accordingly, when theprocessing device 110 analyzes the captured image and the image frame,the processing device 110 can change a coordinate relation between thecaptured image and the image frame. By analogy, the projectors 120_2 to120_N may also execute the same operation.

Description is provided below in more details using schematic diagramsof FIG. 10A to FIG. 10B in combination with the automatic setting methodof FIG. 7.

FIG. 10A is a schematic diagram illustrating a third reference image inan embodiment of the invention. FIG. 10B is a schematic diagramillustrating a fourth reference image in an embodiment of the invention.With reference to FIG. 9, FIG. 10A and FIG. 10B, a projector 1120 may becoupled to the processing device described in the foregoing embodiments.First of all, in FIG. 10A, the processing device executes step S1110 todrive the projector 1120 for projecting a third reference image 1101Aonto the projection plane at the position corresponding to the valididentification region on the projection plane. In the embodiment, theprocessing device executes step S1120 to drive the projector 1120 forcapturing the third reference image 1101A on the projection plane, so asto obtain a third captured image 1103A. Here, the third reference image1101A includes four reference grid points 1102A arranged in aquadrangle. Accordingly, the third captured image 1103A includes a thirdreference image 1101A′ and four references 1102A′, which are tilted. Inthe embodiment, the processing device executes step S1130 to analyze thethird captured image 1103A, so as to obtain four reference coordinatesof the four reference grid points 1102A′ in the third captured image1103A. By doing so, the processing device can establish a coordinateconversion between the four reference grid points 1102A of the thirdreference image 1101A and the four reference grid points 1102A′ of thethird captured image 1103A.

Next, in FIG. 10B, the processing device executes step 1140, in whichthe processing device generates a grid point-filled image 1101B, andprojects the grid point-filled image 1101B onto the projection plane bythe projector 1120. Here, the grid point-filled image 1101B includes agrid point array 1102B formed by a plurality of grid points. In theembodiment, the processing device executes step S1150 to drive the imagecapturing unit of the projector 1120 for capturing a fourth capturedimage 1103B on the projection plane, and analyzes the fourth capturedimage 1103B, so as to obtain each of grid point coordinates of a gridpoint array 1102B′ of a grid point-filled image 1101B′ in the fourthcaptured image 1103B. In the embodiment, the processing device executesstep S1160 so the processing device can establish a coordinateconversion relation between the projection unit and the image capturingunit of the projector 1120 according to the grid point coordinates. Inother words, because the image frame projected by the projection unit ofthe projector 1120 is not identical to the captured image captured bythe image capturing unit, when the processing device analyzes thecaptured image, the processing device can convert coordinate positionsfor each point in the valid identification region in the captured imageinto coordinate positions corresponding to the image frame according tothe coordinate conversion relation.

FIG. 11 is a schematic diagram illustrating two projectors in anembodiment of the invention. FIG. 12 is a schematic diagram illustratinga coordinate integration in the embodiment in FIG. 11. It should benoted that, the automatic setting method described in the embodiment ofFIG. 9 may also be applied in establishment of a coordinate system amongmultiple projectors. With reference to FIG. 11 and FIG. 12, a processingdevice 1210 is coupled to projectors 1220_1 and 1220_2 (two projectorsare taken here as an example). In FIG. 11, an image projection area 1411of the projector 1220_1 is partially overlapping with an imageprojection area 1421 of the projector 1220_2. There is an overlappingarea 1431A between the image projection area 1411 and the imageprojection area 1421. In FIG. 12, an image capturing unit of theprojector 1220_1 obtains captured images 1310 to 1330, and an imagecapturing unit of the projector 1220_2 obtains captured images 1340 to1390.

Hereinafter, detailed description is provided with reference to thecaptured images 1310 to 1390 of FIG. 12. In the embodiment, when theprojector 1220_1 projects the first reference image, the captured image1310 is captured by the image capturing unit of the projector 1220_1.Meanwhile, the image capturing unit of the projector 1220_2 captures thefirst reference image projected by the projector 1220_1 to form thecaptured image 1340. Afterwards, the projector 1220_1 projects an imageframe having reference grid points 1321. Meanwhile, the image capturingunit of the projector 1220_2 captures the image frame having thereference grid points 1321 projected by the projector 1220_1 to form thecaptured image 1350, and so on and so forth, as shown in FIG. 12.

The processing device 1210 analyzes the valid identification region inthe captured image 1310, and then the processing device 1210 analyzesthe valid identification region in the captured image 1340 captured bythe image capturing unit of the projector 1220_2. In the embodiment, theprojector 1220_1 projects the image frame having four reference gridpoints, where positions of the four reference grid points are closer toa right-side of the captured image 1320. The projector 1220_2 does notproject an image frame, and yet the image capturing unit of theprojector 1220_2 does capture the captured image 1350. Accordingly, eachof the captured images 1320 and 1350 include four reference grid points(1321 and 1351). In the embodiment, the processing device 1210 analyzesthe respective four reference grid points (1321 and 1351) in thecaptured images 1320 and 1350, so as to obtain four referencecoordinates and another four reference coordinates of the respectivefour reference grid points (1321 and 1351) in coordinate systems of theprojectors 1220_1 and 1220_2. In the embodiment, the projector 1220_1projects a grid point-filled image. Here, the projector 1220_2 does notproject an image frame, and yet the image capturing unit of theprojector 1220_2 does capture the captured image 1360. Therefore, thecaptured images 1330 and 1360 include the respective grid point-filledimages 1331 and 1361 respectively. In the embodiment, the projectors1220_1 and 1220_2 analyze each grid point in the grid point-filledimages 1331 and 1361 in the captured images 1330 and 1360, respectively,so as to obtain a plurality of grid point coordinates and anotherplurality of grid point coordinates for each grid point in the gridpoint-filled images 1331 and 1361.

In the embodiment, the projector 1220_2 continues to project an imageframe so the operation for analyzing the captured images 1310 to 1330 bythe projector 1220_1 can be executed. In the embodiment, the processingdevice 1210 analyzes four reference grid points 1381 in the capturedimage 1380, so as to obtain four reference coordinates of the fourreference grid points 1381 in the coordinate system of the projector1220_2. Further, the processing device 1210 analyzes each grid point ina grid point-filled image 1391 in the captured image 1390, so as toobtain a plurality of grid point coordinates for each grid point of thegrid point-filled image 1391.

In other words, in the embodiment, the processing device 1210 canperform a coordinate matrix operation according to the obtained gridpoint coordinates, so as to obtain a coordinate conversion relationbetween the projection unit and the image capturing unit of theprojector 1220_1, a coordinate conversion relation between theprojection unit and the image capturing unit of the projector 1220_2 anda coordinate conversion relation between the projectors 1220_1 and1220_2. Also, in the embodiment, the processing device 1210 canintegrate the image projection area 1411 of the projector 1220_1 and theimage projection area 1421 of the projector 1220_2 into one identicalcoordinate system. Nevertheless, enough teaching, suggestion, andimplementation illustration for the coordinate conversion relationsdescribed in the embodiments of the invention may be obtained withreference to common knowledge in the related art, which is not repeatedhereinafter.

It should be noted that, in the embodiment, the processing device 1210can perform a coordinate conversion on the captured images obtained bythe projectors 1220_1 and 1220_2 according to each of the coordinateconversion relations, and adjust the captured images as shown in FIG.13A and FIG. 13B to facilitate an image analysis in the followingembodiments.

FIG. 13A is a schematic diagram illustrating two image projection areasoverlapping with each other in the embodiment of FIG. 11. FIG. 13B is aschematic diagram illustrating an integrated image frame area in theembodiment of FIG. 11. With reference to FIG. 11, FIG. 13A and FIG. 13B,in the embodiment, image capturing areas 1410 and 1420 of the projectors1220_1 and 1220_2 are partially overlapping with each other, and theimage projection areas 1411 and 1421 (illustrated by solid lines) haveoverlapping areas 1411A/1421A. In FIG. 13A, before the projectors 1220_1and 1220_2 are integrated into the identical coordinate system, fourvertex coordinates of the image capturing area 1410 are (X1, Y1), (X2,Y1), (X1, Y2) and (X2, Y2), respectively. Four vertex coordinates of theimage capturing area 1420 are (X3, Y1), (X4, Y1), (X3, Y2) and (X4, Y2),respectively. For the processing device 1210, the coordinate system ofthe image capturing area 1410 of the projector 1220_1 is different fromthat of the image capturing area 1420 of the projector 1220_2.

For instance, the image capturing area 1410 and the image capturing area1420 are located at the same height in a horizontal direction, but notlimited thereto.

Definitions of the image capturing units of the projectors 1220_1 and1220_2 are 752×480 pixels. In other words, the vertex coordinates (X1,Y1), (X2, Y1), (X1, Y2) and (X2, Y2) of the image capturing area 1410may be (0,0), (752,0), (0,480) and (752,480), respectively, and thevertex coordinates (X3, Y1), (X4, Y1), (X3, Y2) and (X4, Y2) of theimage capturing area 1420 may also be (0,0), (752,0), (0,480) and(752,480), respectively. In this example, the image projection area 1411and the image projection area 1421 are not located at the same height inthe horizontal direction, and the image projection area 1411 and theimage projection area 1421 have the overlapping areas 1411A/1421A.

In this example, sizes of the image projection area 1411 and the imageprojection area 1421 are 480×360. Taking the coordinate system of theimage capturing area 1410 for example, left and right borders of theimage projection area 1411 are, for example, located at positions wherea border a1=136 and a border a2=616 in the coordinate system of theimage capturing area 1410, and upper and lower borders of the imageprojection area 1411 are, for example, located at positions where aborder b1=100 and a border b2=460 in the coordinate system of the imagecapturing area 1410. Taking the coordinate system of the image capturingarea 1420 for example, left and right borders of the image projectionarea 1421 are, for example, located at positions where a border a3=136and a border a4=616 in the coordinate system of the image capturing area1420, and upper and lower borders of the image projection area 1421 are,for example, located at positions where a border b3=60 and a borderb4=420 in the coordinate system of the image capturing area 1410.

In this example, the processing device 1210 can determine that the imageprojection area 1411 and the image projection area 1421 have the imageoverlapping areas 1411A/1421A in the horizontal direction. Also, theprocessing device 1210 separately adjusts a luminance value of a partialimage frame (the image overlapping area 1411A of the image projectionarea 1411) projected by the projector 1220_1 and a luminance value ofanother partial image frame (the image overlapping area 1421A of theimage projection area 1421) projected by the projector 1220_2 in theimage overlapping areas 1411A/1421A. In other words, the processingdevice 1210 can determine area sizes of the image projection area 1411and the image projection area 1421 respectively occupied by the imageoverlapping areas 1411A/1421A, and lower the luminance values of theimage frames in the image overlapping areas 1411A/1421A for theprojectors 1220_1 and 1220_2, so as to prevent the brightness of theimage frames in the image overlapping areas 1411A/1421A from beingoverly bright.

Also, the processing device 1210 can further determine a maximumhorizontal distance (from a1 to a4) and a minimum vertical distance(from b1 to b4) respectively in a horizontal direction and a verticaldirection of the boundaries of the image projection area 1411 and theimage projection area 1421. As such, in this example, the processingdevice 1210 decides an integrated image frame area 1431 as shown in FIG.13B according to the maximum horizontal distance (from a1 to a4) and theminimum vertical distance (from b1 to b4).

Specifically, the processing device 1210 can execute the integrationoperation for the coordinate system of FIG. 12 to integrate the imagecapturing area 1410 and the image capturing area 1420 into an imagecapturing area 1430. In this example, a size of the image capturing area1430 is 1072×480, and a size of the integrated image frame area 1431 is800×280. Left and right borders of the image projection area 1431 are,for example, located at positions where a border a1′=136 and a bordera4′=936 in a coordinate system of the image capturing area 1430, andupper and lower borders of the image projection area 1411 are, forexample, located at positions where a border b1′=100 and a borderb4′=380 in the coordinate system of the image capturing area 1430. Also,left and right borders of the image overlapping area 1431A are, forexample, located at positions where border a3′=456 and a border a2′=616in the coordinate system of the image capturing area 1430. In otherwords, the processing device 1210 can automatically integrate the imageprojection areas 1411 and 1421 of the projectors 1220_1 and 1220_2 intothe integrated image frame area 1431 so one integrated image frame canbe displayed onto the projection plane. Further, in the embodiment, theprocessing device 1210 can calculate an overlapping image ratio of theimage overlapping area 1431A in the horizontal direction, which is 20%(i.e., (616-456)/(936-136)). According to the overlapping image ratio ofthe image overlapping area 1431A in the horizontal direction, theprocessing device 1210 can automatically adjust the brightness of theimage frame in 20% of the image projection area 1411 on the right-sideand can automatically adjust the brightness of the image frame in 20% ofthe image projection area 1421 on the left-side so the integrated imageframe displayed in the integrated image frame area 1431 can have theeffectiveness of even brightness.

In summary, with the projection system and the automatic setting methodthereof according to the invention, the respective setting parameters ofmultiple projectors of the projection system may be automatically set,and the projection modes and the disposing sequences of the projectorsmay also be automatically determined such that the projection system canbe easily set up based on various projection requirements. Moreover,with the projection system and the automatic setting method thereofaccording to the invention, the image frames of the projectors of theprojection system may be automatically adjusted and the size ranges ofthe image frames of the projectors may also be automatically adjustedsuch that the image frames of the projectors may be integrated into oneintegrated image frame with favorable projection quality.

The foregoing description of the preferred embodiments of the inventionhas been presented for purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform or to exemplary embodiments disclosed. Accordingly, the foregoingdescription should be regarded as illustrative rather than restrictive.Obviously, many modifications and variations will be apparent topractitioners skilled in this art. The embodiments are chosen anddescribed in order to best explain the principles of the invention andits best mode practical application, thereby to enable persons skilledin the art to understand the invention for various embodiments and withvarious modifications as are suited to the particular use orimplementation contemplated. It is intended that the scope of theinvention be defined by the claims appended hereto and their equivalentsin which all terms are meant in their broadest reasonable sense unlessotherwise indicated. Therefore, the term “the invention”, “the presentinvention” or the like does not necessarily limit the claim scope to aspecific embodiment, and the reference to particularly preferredexemplary embodiments of the invention does not imply a limitation onthe invention, and no such limitation is to be inferred. The inventionis limited only by the spirit and scope of the appended claims.Moreover, these claims may refer to use “first”, “second”, etc.following with noun or element. Such terms should be understood as anomenclature and should not be construed as giving the limitation on thenumber of the elements modified by such nomenclature unless specificnumber has been given. The abstract of the disclosure is provided tocomply with the rules requiring an abstract, which will allow a searcherto quickly ascertain the subject matter of the technical disclosure ofany patent issued from this disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Any advantages and benefits described may notapply to all embodiments of the invention. It should be appreciated thatvariations may be made in the embodiments described by persons skilledin the art without departing from the scope of the invention as definedby the following claims. Moreover, no element and component in thedisclosure is intended to be dedicated to the public regardless ofwhether the element or component is explicitly recited in the followingclaims.

What is claimed is:
 1. An automatic setting method, adapted to aprojection system, wherein the projection system comprises a processingdevice and a first projector, the first projector comprises a firstprojection unit and a first image capturing unit, and the automaticsetting method comprises: projecting a first reference image onto aprojection plane by the first projection unit, and capturing the firstreference image on the projection plane by the first image capturingunit to obtain a first captured image; projecting a second referenceimage onto the projection plane by the first projection unit, andcapturing the second reference image on the projection plane by thefirst image capturing unit to obtain a second captured image; andcomparing the first captured image and the second captured image toobtain a position of an image region having a pixel value change amongthe first captured image and the second captured image, and defining theposition of the image block having the pixel value change as a valididentification region.
 2. The automatic setting method according toclaim 1, wherein the first reference image is a pure-white image, andthe second reference image is a pure-black image.
 3. The automaticsetting method according to claim 2, wherein the step of comparing thefirst captured image and the second captured image to obtain theposition of the image region having the pixel value change among thefirst captured image and the second captured image, and defining theposition of the image block having the pixel value change as the valididentification region comprises: subtracting pixel values of a pluralityof pixels of the first captured image and the second captured image fromeach other to obtain a pixels-subtracted image; and analyzing thepixels-subtracted image to determine a region having the pixel valuesgreater than a threshold value in the pixels-subtracted image, anddefining the region having the pixel values greater than the thresholdvalue as the valid identification region.
 4. The automatic settingmethod according to claim 3, wherein the step of comparing the firstcaptured image and the second captured image to obtain the position ofthe image region having the pixel value change among the first capturedimage and the second captured image, and defining the position of theimage block having the pixel value change as the valid identificationregion comprises: analyzing the pixels-subtracted image to determine aregion having the pixel values less than the threshold value in thepixels-subtracted image, and defining the region having the pixel valuesless than the threshold value as a non-valid identification region. 5.The automatic setting method according to claim 1, further comprising:projecting a third reference image onto the projection plane at theposition corresponding to the valid identification region by the firstprojection unit; capturing the third reference image on the projectionplane by the first image capturing unit to obtain a third capturedimage, wherein the third reference image has four reference grid pointsarranged in a quadrangle; analyzing the third captured image to obtainfour reference coordinates of the four reference grid points in thethird captured image; generating a grid point-filled image according tothe four reference coordinates of the four reference grid points, andprojecting the grid point-filled image onto the projection plane by theprojection unit, wherein the grid point-filled image comprises a gridpoint array formed by a plurality of grid points; capturing the gridpoint-filled image on the projection plane by the first image capturingunit so as to obtain a fourth captured image, and analyzing the fourthcaptured image to obtain a plurality of grid point coordinates of thegrid points in the fourth captured image; and establishing a firstcoordinate conversion relation between the first projection unit and thefirst image capturing unit according to the plurality of grid pointcoordinates.
 6. The automatic setting method according to claim 5,wherein the projection system further comprises a second projector, andthe second projector comprises a second projection unit and a secondimage capturing unit, wherein a first image projection area of the firstprojector is partially overlapping with a second image projection areaof the second projector, and the automatic setting method furthercomprises: capturing a part of the third reference image on theprojection plane by the second image capturing unit to obtain a fifthcaptured image; analyzing the fifth captured image to obtain anotherfour reference coordinates of the four reference grid points in thefifth captured image; and establishing a second coordinate conversionrelation between the first projector and the second projector accordingto the four reference coordinates and the another four referencecoordinates of the four reference grid points.
 7. The automatic settingmethod according to claim 6, further comprising: capturing the fourthreference image on the projection plane by the second image capturingunit to obtain a sixth captured image; analyzing the sixth capturedimage to obtain another plurality of grid point coordinates of the gridpoints in the sixth captured image; and integrating the plurality ofgrid point coordinates in the first image projection area and theanother plurality of grid point coordinates in the second imageprojection area into one identical coordinate system according to thecoordinate conversion relations.
 8. The automatic setting methodaccording to claim 7, further comprising: determining image overlappingareas of the first image projection area and the second image projectionarea, so as to separately adjust a first luminance value of a partialprojection image projected by the first projector and a second luminancevalue of another partial projection image projected by the secondprojector in the image overlapping areas.
 9. The automatic settingmethod according to claim 8, further comprising: determining a maximumhorizontal distance and a minimum vertical distance respectively in ahorizontal direction and a vertical direction of a plurality ofboundaries of the first image projection area and the second imageprojection area; and deciding an integrated projection image areaaccording to the maximum horizontal distance and the minimum verticaldistance.
 10. A projection system, comprising: a processing device; anda first projector, coupled to the processing device, and the firstprojector comprising: a first projection unit, configured to project afirst reference image onto a projection plane; and a first imagecapturing unit, configured to capture the first reference image on theprojection plane to obtain a first captured image, wherein theprocessing device projects a second reference image onto the projectionplane by the first projection unit, and the processing device capturesthe second reference image on the projection plane by the first imagecapturing unit to obtain a second captured image; the processing deviceis adapted to compare the first captured image and the second capturedimage to obtain a position of an image region having a pixel valuechange among the first captured image and the second captured image, andthe processing device defines the position of the image block having thepixel value change as a valid identification region.
 11. The projectionsystem according to claim 10, wherein the first reference image is apure-white image, and the second reference image is a pure-black image.12. The projection system according to claim 11, wherein the processingdevice subtracts pixel values of a plurality of pixels of the firstcaptured image and the second captured image from each other to obtain apixels-subtracted image, the processing device analyzes thepixels-subtracted image to determine a region having the pixel valuesgreater than a threshold value in the pixels-subtracted image, and theprocessing device defines the region having the pixel values greaterthan the threshold value as the valid identification region.
 13. Theprojection system according to claim 12, wherein the processing deviceanalyzes the pixels-subtracted image to determine a region having thepixel values less than the threshold value in the pixels-subtractedimage, and the processing device defines the region having the pixelvalues less than the threshold value as a non-valid identificationregion.
 14. The projection system according to claim 10, wherein theprocessing device projects a third reference image onto the projectionplane at the position corresponding to the valid identification regionby the first projection unit, wherein the processing device captures thethird reference image on the projection plane by the first imagecapturing unit to obtain a third captured image, wherein the thirdreference image has four reference grid points arranged in a quadrangle,wherein the processing device analyzes the third captured image toobtain four reference coordinates of the four reference grid points inthe third captured image, wherein the processing device projects thegrid point-filled image onto the projection plane by the projectionunit, wherein the grid point-filled image comprises a grid point arrayformed by a plurality of grid points, wherein the processing devicecaptures the grid point-filled image on the projection plane by thefirst image capturing unit so as to obtain a fourth captured image ofthe projection plane, and analyzes the fourth captured image to obtain aplurality of grid point coordinates of the grid points in the fourthcaptured image, wherein the processing device establishes a firstcoordinate conversion relation between the first projection unit and thefirst image capturing unit according to the plurality of grid pointcoordinates.
 15. The projection system according to claim 14, furthercomprising: a second projector, coupled to the processing device,wherein the second projector comprises: a second projection unit; and asecond image capturing unit, configured to capture a part of the thirdreference image on the projection plane to obtain a fifth capturedimage, wherein the processing device analyzes the fifth captured imageto obtain another four reference coordinates of the four reference gridpoints in the fifth captured image, wherein the processing deviceestablishes a second coordinate conversion relation between the firstprojector and the second projector according to the four referencecoordinates and the another four reference coordinates of the fourreference grid points.
 16. The projection system according to claim 15,wherein the processing device captures the fourth reference image on theprojection plane by the second image capturing unit to obtain a sixthcaptured image, wherein the processing device analyzes the sixthcaptured image to obtain another plurality of grid point coordinates ofthe grid points in the sixth captured image, wherein the processingdevice integrates the plurality of grid point coordinates in the firstimage projection area and the another plurality of grid pointcoordinates in the second image projection area into one identicalcoordinate system according to the coordinate conversion relations. 17.The projection system according to claim 16, wherein the processingdevice determines image overlapping areas of the first image projectionarea and the second image projection area, so as to separately adjust afirst luminance value of a partial projection image projected by thefirst projector and a second luminance value of another partialprojection image projected by the second projector in the imageoverlapping areas.
 18. The projection system according to claim 17,wherein the processing device determines a maximum horizontal distanceand a minimum vertical distance respectively in a horizontal directionand a vertical direction of a plurality of boundaries of the first imageprojection area and the second image projection area, wherein theprocessing device decides an integrated projection image area accordingto the maximum horizontal distance and the minimum vertical distance.